Wall Street executives and hedge fund managers are so far the most conspicuous donors to "super political action committees," followed by titans of energy. But for raw impact, no one beats casino billionaire Sheldon Adelson, whose extended family has contributed $11 million to a super PAC backing Newt Gingrich.

Recent financial disclosures from super PACs give insight into which people, corporations, and unions are writing big checks in hopes the super PACs can succeed in influencing the 2012 presidential race. Mr. Adelson's contributions, say political analysts, helped Mr. Gingrich to get back in the race after fourth-place showings in Iowa and New Hampshire.

The Adelson-Gingrich connection dates from the candidate’s tenure as US speaker of the House in the late 1990s, when the two men conferred over legislation in support of Israel. Those ties are especially on display in Nevada, which holds its presidential caucuses Saturday.

As of Feb. 2, the Gingrich campaign itself had yet to buy TV, cable, or radio ads in the Las Vegas media market. But the Adelson-funded Winning Our Future super PAC did give Gingrich a radio presence in the run-up to the Nevada caucuses, running 203 pro-Gingrich ads and 62 anti-Mitt Romney ads, according to Media Monitors, based in White Plains, N.Y. The Romney campaign and Restore Our Future, a super PAC backing Romney, otherwise dominated TV, cable, and radio in the Las Vegas market, producing 1,116 spots overall, compared with 277 for Gingrich, 256 for Ron Paul, and seven for Rick Santorum.

Typically, the Nevada caucuses begin at 9 a.m. and end at 3 p.m. But in an 11th-hour decision, the Nevada Republican Party, with support from Mr. Adelson, added a special caucus venue at the Adelson Educational Campus, a private school in Las Vegas, to encourage participation by Orthodox Jews after sundown. This caucus begins at 7 p.m. As a footnote, Gingrich is staying at the Venetian resort, a subsidiary of Adelson’s Las Vegas Sands.

Often viewed as a conservative counterpart of financier George Soros – whose millions helped fund organizations that set out to defeat President Bush in the 2004 campaign – Adelson has been an ATM machine for GOP candidates and party organizations, especially in his home state of Nevada and other states with gambling interests.

By contrast, Adelson wrote a $2,500 check to the Gingrich presidential campaign back in August, the maximum allowed under campaign-finance law.

Until the US Supreme Court’s 2010 decision Citizens United v. Federal Elections Commission, federal law limited the amount individuals and corporations could contribute to directly advocate for or against a candidate. In this decision, the Supreme Court called such advocacy an expression of political speech that government has no business to regulate, but also provided that Congress could require corporations and individuals to disclose their spending.

“Disclosure permits citizens and shareholders to react to the speech of corporate entities in a proper way,” said Justice Anthony Kennedy, writing for the majority.

So, what are citizens to make of the largest contributions in support of a political candidate in US political history? If Adelson’s funding proves to be a game-changer in Gingrich’s quest for the White House, does the casino operator expect anything in return?

Both men describe their common cause as the survival of the state of Israel. “This one-sided continuing pressure that says it’s always Israel’s fault, no matter how bad the other side is, has to stop,” Gingrich said at the Republican Jewish Coalition’s 2012 Republican candidates forum on Dec. 7. In an interview with the Jewish Channel on Dec. 10, Gingrich described the Palestinians as “an invented people.”

Asked why Adelson gave Winning Our Future $5 million (Adelson’s wife, Miriam, delivered a second $5 million), Gingrich said in an interview on NBC: “He knows I’m very pro-Israel, and that’s the central value of his life.” Miriam Adelson was born in Israel and served in the Israeli military.

“Our motivation for helping Newt is simple and should not be mistaken for anything other than the fact that we hold our friendship with him very dear and are doing what we can as private citizens to support his candidacy,” the Adelsons said in a statement.

But any point of congruence between the interests of a corporation and the capacity of a politician to help out is grist for alternative versions of possible motives behind a big gift.

What's known is that Adelson fought hard and successfully in the 1990s to block unionization at his Las Vegas casinos. Currently, the Department of Justice and the US Securities Exchange Commission are investigating his Las Vegas Sands Corp. for alleged bribery of foreign officials in Macau, where he owns a casino that now produces more revenue than his Las Vegas operations.

“Whenever you have big-money donations, there is always a question of motivation,” says Ed Bender of the National Institute on Money in State Politics.

The gambling industry itself is going through a building surge, he adds, noting that “many states are opening up to gambling as a way to generate revenue.

“This is the third major expansion of gambling in the history of the country, and every time we do this we wind up with a major corruption wave,” he says.

Gambling interests contributed outsized donations to other super PACs, as well. The Choctaw Nation of Oklahoma, for example, which owns seven casinos in the southeast part of the state, on Dec. 29 contributed $50,000 to a super PAC supporting Texas Gov. Rick Perry, when prospects for the governor's presidential run were already tanking. But the governor is not term-limited in Texas, analysts note. A super PAC contribution can also be seen as a way to give outsized contributions to support a sitting governor, otherwise banned by Texas campaign finance law.

“Generally speaking, when the tribes give it’s some kind of gambling issue,” says Bill Allison, editorial director at the Sunlight Foundation, a public-interest group in Washington. A spokeswoman for the Choctaw Nation of Oklahoma did not return a request for comment.